CN114487865A - Battery SOC estimation method, battery management system and computer readable storage medium - Google Patents

Abstract

The invention discloses a battery SOC estimation method, a battery management system and a computer readable storage medium. The method comprises the following steps: acquiring actual measurement data of the battery, wherein the actual measurement data of the battery comprises: acquiring actually measured data of the battery, wherein the actually measured data of the battery comprises actually measured current, actually measured voltage, actually measured SOC and actually measured accumulated historical electric quantity; inquiring a correction data table according to the actually measured current and the actually measured voltage, and acquiring SOC upper limit correction data and SOC lower limit correction data matched with the actually measured current and the actually measured voltage; determining an SOC upper limit threshold and an SOC lower limit threshold according to the actually measured accumulated historical electric quantity, the SOC upper limit correction data and the SOC lower limit correction data; and correcting the actual measurement SOC by adopting an SOC upper limit threshold and an SOC lower limit threshold to obtain the target SOC. The target SOC estimated by the battery SOC method is high in accuracy and small in error with the actual SOC of the battery, so that the requirements of high accuracy, low resource requirement and high instantaneity can be met for SOC estimation.

Description

Battery SOC estimation method, battery management system and computer-readable storage medium

technical field

The present invention relates to the technical field of battery management, and in particular, to a battery SOC estimation method, a battery management system and a computer-readable storage medium.

Background technique

SOC (abbreviation for State Of Charge, that is, battery state of charge or remaining power) refers to the ratio of the remaining dischargeable power after a battery has been used for a period of time or left unused for a long time to its fully charged state of charge. SOC is an important parameter of the entire battery energy storage system. Accurate estimation of SOC can realize rational utilization of battery energy, prevent battery overcharge or overdischarge and other unreasonable use problems, so as to improve battery service life.

Existing SOC estimation methods include, but are not limited to, the ampere-hour integration method, the real-time voltage correction method, the open-circuit voltage method, and the neural network method. Each SOC estimation method has its own advantages and disadvantages. The ampere-hour integration method realizes SOC estimation based on the accumulation of current. It is simple to operate and requires low resources. However, it depends on the accuracy of the sampling current. The calibration requirements for high voltage when full and low voltage when emptying are large, and the accuracy is low. The real-time voltage correction method is to estimate the SOC based on the real-time voltage, real-time current and the known charge-discharge voltage curves of each current. When the voltage changes significantly or the battery is used at a high frequency, the SOC can be accurately estimated, and the error is small, but when the voltage changes are not high. Obviously or when the battery usage frequency is low, the accuracy of SOC estimation is low and the error is large. The open-circuit voltage method is to measure the battery after it has not been charged and discharged for several hours, and use the open-circuit voltage curve to estimate the SOC. The neural network method refers to the use of neural networks to correct and accumulate battery data collected under different operating conditions for SOC estimation.

SUMMARY OF THE INVENTION

Embodiments of the present invention provide a battery SOC estimation method, a battery management system, and a computer-readable storage medium, so as to solve the problems that existing SOC estimation methods cannot take into account high accuracy, low operating resources, and strong real-time performance.

An embodiment of the present invention provides a battery SOC estimation method, including:

Obtaining measured data of the battery, the measured data of the battery including the measured current, the measured voltage, the measured SOC and the measured accumulated historical power;

Query the correction data table according to the measured current and the measured voltage, and obtain the SOC upper limit correction data and the SOC lower limit correction data that match the measured current and the measured voltage;

determining the SOC upper limit threshold and the SOC lower limit threshold according to the measured accumulated historical power, the SOC upper limit correction data and the SOC lower limit correction data;

The measured SOC is corrected by using the SOC upper limit threshold and the SOC lower limit threshold to obtain a target SOC.

Preferably, the correction data table is inquired according to the measured current and the measured voltage, and the SOC upper limit correction data and the SOC lower limit correction data matching the measured current and the measured voltage are obtained, including:

Query the correction data table based on the measured current, and obtain the SOC candidate correction data that matches the preset current in the correction data table and the measured current;

Based on the measured voltage and the SOC candidate correction data, obtain the SOC upper limit correction data and the SOC lower limit correction data;

Wherein, the SOC candidate correction data includes: preset current, preset voltage, preset SOC, and preset accumulated historical power.

Preferably, the querying the correction data table based on the measured current, and obtaining the SOC candidate correction data in which the preset current in the correction data table matches the measured current, includes:

If the preset current in the correction data table is equal to the measured current, the first correction data corresponding to the preset current is used as the SOC candidate correction data;

If the preset current in the correction data table is not equal to the measured current, acquire the second correction data and the third correction data in the correction data table, based on the measured current, the second correction data and the The third correction data is to obtain SOC candidate correction data, wherein the preset current in the second correction data is smaller than the measured current, and the preset current in the third correction data is greater than the measured current.

Preferably, the acquiring SOC candidate correction data based on the measured current, the second correction data and the third correction data includes:

Using a data estimation formula to process the measured current, the second correction data and the third correction data, to obtain the SOC candidate correction data;

The data estimation formula is ST=(Sa-Sb)*(IT-Ib)/(Ia-Ib)+Sb; if Sa is the preset voltage in the second correction data, Sb is the third correction data If the preset voltage of , ST is the preset voltage in the SOC candidate correction data; if Sa is the preset SOC in the second correction data, Sb is the preset SOC in the third correction data, Then ST is the preset SOC in the SOC candidate correction data; if Sa is the preset cumulative historical power in the second modified data, and Sb is the preset cumulative historical power in the third modified data, then ST is the preset accumulated historical power in the SOC candidate correction data; IT is the measured current; Ia is the preset current in the second correction data; Ib is the preset current in the third correction data.

Preferably, the acquiring the SOC upper limit correction data and the SOC lower limit correction data based on the measured voltage and the SOC candidate correction data includes:

If the preset voltage in the SOC candidate correction data is greater than the measured voltage, the difference between the preset voltage and the measured voltage in the SOC candidate correction data is determined as the first difference, and the determining the SOC candidate correction data with the smallest first difference as the SOC upper limit correction data;

If the preset voltage in the SOC candidate correction data is smaller than the measured voltage, the difference between the measured voltage and the preset voltage in the SOC candidate correction data is determined as a second difference, and the The SOC candidate correction data with the smallest second difference is determined as the SOC lower limit correction data.

Preferably, the determining of the SOC upper limit threshold and the SOC lower limit threshold according to the measured accumulated historical power, the SOC upper limit correction data and the SOC lower limit correction data includes:

Obtain an upper limit error value according to the measured cumulative historical power and the preset cumulative current error and preset cumulative historical power in the SOC upper limit correction data, and compare the preset SOC in the SOC upper limit correction data with the upper limit error The sum of the values is determined as the SOC upper threshold;

Obtain a lower limit error value according to the measured cumulative historical power and the preset cumulative current error and preset cumulative historical power in the SOC lower limit correction data, and compare the preset SOC in the SOC lower limit correction data with the lower limit error The difference between the values is determined as the SOC lower limit threshold.

Preferably, the use of the SOC upper limit threshold and the SOC lower limit threshold to correct the measured SOC to obtain a target SOC includes:

If the measured SOC is greater than the SOC upper limit threshold, determining the preset SOC in the SOC upper limit correction data as the target SOC;

If the measured SOC is less than the SOC lower limit threshold, determining the preset SOC in the SOC lower limit correction data as the target SOC;

If the measured SOC is not less than the lower SOC threshold, and the measured SOC is not greater than the SOC upper threshold, the measured SOC is determined as the target SOC.

Preferably, the measured battery data further includes an actual measured accumulated current error;

After acquiring the actual measured data of the battery, the battery SOC estimation method further includes:

comparing the measured accumulated current error and the current error tolerance value;

If the measured cumulative current error is greater than the current error tolerance value, execute the query and correction data table according to the measured current and the measured voltage, and obtain the SOC upper limit that matches the measured current and the measured voltage Correction data and SOC lower limit correction data;

If the measured cumulative current error is not greater than the current error tolerance value, the configuration correction data in the correction data table is updated based on the battery measured data.

Preferably, the updating of the configuration correction data in the correction data table based on the actual measured data of the battery includes:

Obtain all the SOC preliminary selection correction data in the correction data table that match the preset SOC and the measured SOC, and determine the SOC preliminary selection correction data adjacent to the preset current and the measured current as the first correction data. First correction data to be updated and second correction data to be updated, the first correction data to be updated and the second correction data to be updated are determined as the correction data to be updated for the SOC, and the predetermined correction data in the first correction data to be updated is determined. It is assumed that the current is less than the measured current, and the preset current in the second to-be-updated correction data is greater than the measured current;

processing the battery measured data and the SOC to-be-updated correction data, to obtain the measured-unreliable value corresponding to the battery's measured data and the to-be-updated unreliable value corresponding to the SOC to-be-updated correction data;

If the unreliable value to be updated is empty, or the measured unreliable value is smaller than the unreliable value to be updated, the SOC correction data to be updated is updated by using the battery measured data.

Preferably, the processing of the measured battery data and the SOC to-be-updated correction data is performed, and the measured unreliable value corresponding to the battery's measured data and the to-be-updated unreliable value corresponding to the SOC to-be-updated correction data are obtained, include:

The measured unreliable value formula of QT(CTBm)=ABS(IT-CTBm)*f+DT*g+(CT-CT)*h is used to calculate the measured battery data, and the measured unreliability corresponding to the measured battery data is obtained. value;

Use the unreliable value formula to be updated Qn(CTBm)=ABS(In-CTBm)*f+Dn*g+(CT-Cn)*h to calculate the SOC to-be-updated corrected data and the battery measured data, and obtain all The unreliable value to be updated corresponding to the SOC to be updated correction data;

Wherein, QT(CTBm) is the measured unreliable value corresponding to the measured data of the battery; CTBm is the preset current; ABS is the absolute value function; IT, DT and CT are the measured current and the measured cumulative value of the measured battery data respectively. Current error and measured accumulated historical power; Qn (CTBm) is the unreliable value to be updated corresponding to the SOC to be updated correction data; In, Dn and Cn are the preset current and preset corresponding to the SOC to be updated correction data, respectively Cumulative current error and preset cumulative historical power; f is the current coefficient; g is the cumulative current error coefficient; h is the cumulative historical power coefficient.

Embodiments of the present invention further provide a battery management system, including a memory, a processor, and a computer program stored in the memory and executable on the processor, where the processor implements the above when executing the computer program Describe the battery SOC estimation method.

An embodiment of the present invention further provides a computer-readable storage medium, where the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, implements the battery SOC estimation method as described above.

The above-mentioned battery SOC estimation method, battery management system and computer-readable storage medium, query a correction data table according to the measured current and the measured voltage, and quickly determine the SOC upper limit correction data and the SOC lower limit correction data, so that the SOC estimation requires low resources and Helps to provide real-time SOC estimation; then determine the SOC upper threshold and the SOC lower threshold based on the measured accumulated historical power, the SOC upper limit correction data and the SOC lower limit correction data, and use the SOC upper threshold and SOC lower threshold to evaluate the actual measurement. The SOC is corrected so that the output target SOC has a high accuracy and a small error with the actual SOC of the battery, so that the SOC estimation can take into account the needs of high accuracy, low resource requirements and high real-time performance.

Description of drawings

In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the following briefly introduces the drawings that are used in the description of the embodiments of the present invention. Obviously, the drawings in the following description are only some embodiments of the present invention. , for those of ordinary skill in the art, other drawings can also be obtained from these drawings without creative labor.

FIG. 1 is a flowchart of a battery SOC estimation method in an embodiment of the present invention;

FIG. 2 is another flowchart of a battery SOC estimation method in an embodiment of the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

The battery SOC estimation method provided by the embodiment of the present invention can be applied in a battery management system (BATTERY MANAGEMENT SYSTEM, hereinafter referred to as BMS), the BMS is connected to the battery, and is used to estimate the SOC of the battery, so that the estimation The obtained target SOC has the advantages of high accuracy, low resource requirements and high real-time performance.

In this embodiment, a correction data table is pre-stored in the memory of the BMS, and the correction data table is a data table that pre-records correction data of different configurations. The configuration correction data refers to the data formed and recorded in the memory of the BMS according to the operating conditions of the battery before the system time for obtaining the measured battery data, which can be understood as the data to be called to realize the estimation and correction of the measured SOC.

Due to the limited storage resources in the BMS, the configuration correction data in the correction data table is limited. According to the storage resources provided by the BMS, X*Y configuration correction data can be stored in the correction data table, where X is the number of preset SOCs , for example, if the preset SOC values are 5%, 15%, 25%, 75%, 85% and 95%, then X is 6; Y is the number of preset currents, if the preset current values are 0.2C, 0.5C, 0.9C, 1C and 2.2C, then Y is 5, then 30 configuration correction data are stored in the correction data table.

As an example, according to the test data formed by the battery during the test operation in advance, draw X voltage-current measured curves corresponding to the preset SOC, and then Y preset currents determined according to the current sampling rule, so that the preset current and The voltage-current measured curve determines the preset voltage. In this example, the Y preset currents can be determined by using the arithmetic difference rule to minimize the difference and help reduce the error of the subsequent SOC estimation. At this time, the Y preset currents are the preset currents CTBm, Wherein, 1≦m≦Y; as shown above, the preset currents CTB1=0.2, CTB2=0.7, CTB3=1.2, CTB4=1.7, and CTB5=2.2.

In this example, the configuration correction data includes preset current, preset voltage, preset SOC, preset accumulated current error and preset accumulated historical power, and can use [SOCn, In, Vn, Dn, Cn] to represent the nth configuration Correction data, where 1≦n≦X*Y. The preset SOC is a pre-configured SOC of the battery that may need to be corrected, and can be represented by SOCn. The preset current refers to a pre-configured current of the battery working process that may need to be corrected, which may be represented by In, and may specifically be a charging current or a discharging current. The preset voltage refers to the voltage required for realizing the correction of SOC estimation, which is formed and recorded before the system time when the measured battery data is received, and can be represented by Vn. The preset accumulated current error refers to the accumulation of all error currents before the system time when the measured battery data is received, which can be represented by Dn. The preset accumulated historical power refers to the accumulation of all power before the system time when the measured battery data is received, which can be represented by Cn. For example, when the real-time voltage correction method is used to estimate the SOC, the preset SOC, the preset current and the preset voltage are known specific sampling points in each current charge-discharge voltage curve.

In one embodiment, as shown in FIG. 1 , a method for estimating battery SOC is provided, and the method is applied to a BMS as an example for description, including the following steps:

S11: Acquire actual battery data, which includes measured current, measured voltage, measured SOC, and measured accumulated historical power.

The battery measured data refers to the battery-related data acquired by the BMS in real time. The measured current refers to the current obtained by the BMS during the working process of the battery, which can be represented by IT _. It can be understood as the current determined when the SOC algorithm method is used for processing. Specifically, it can be the charging current or the discharging current. The measured voltage refers to the voltage obtained by the BMS in real time during the working process of the battery, which can be represented by V _T , which can be understood as the voltage determined when the SOC algorithm method is used for processing. The measured SOC is the SOC of the battery obtained in real time by the BMS, which can be represented by SOC _T , which can be understood as the estimated SOC determined by the SOC estimation method. The measured accumulated historical power is the accumulation of all the power after receiving the actual measured data of the battery, which can be represented by _CT . For example, in the process of battery charging, the measured cumulative historical power is the accumulation of all charged power; during the battery discharge process, the measured cumulative historical power is the cumulative of all discharged powers. It can be understood that the measured accumulated historical power includes the accumulation of all accumulated historical power before the system time and the power in the current battery measured data.

As an example, the BMS acquires the measured battery data in real time. The measured battery data includes the measured current, measured voltage, measured SOC, measured accumulated current error, and measured accumulated historical power. [SOC _T , _IT , V _T , D _T , C _T ] represents the measured data of the battery. For example, during the charging process of the battery, when the measured current of 1.2C is used to charge to the measured voltage V0, the real-time voltage correction method can be used to estimate the SOC of the measured current of 1.2C and the measured voltage V0 to obtain the measured SOC0, and calculate with the configuration correction data. The measured cumulative current error D0 and the measured cumulative historical power C0 are used to obtain the measured battery data [SOC0, 1.2C, V0, D0, C0].

S12: Query the correction data table according to the measured current and the measured voltage, and obtain the SOC upper limit correction data and the SOC lower limit correction data matching the measured current and the measured voltage.

Because the real-time voltage correction method is used for SOC estimation, when the SOC is in the middle stage (such as 30%-70%), the SOC estimation accuracy is high, and the error between the estimated measured SOC and the actual battery SOC is small; If the SOC is in the low range (such as 0-30%) or high range (such as 70%-100%), the accuracy of the SOC estimation is low, and the error between the estimated measured SOC and the actual SOC of the battery is large, which needs to be corrected. Therefore, it is necessary to query the correction data table according to the measured current and measured voltage, and obtain the SOC upper limit correction data and SOC lower limit correction data that match the measured current and measured voltage, so as to use the SOC upper limit correction data and the SOC lower limit correction data for correction.

The correction data table is a data table in which correction data of different configurations are recorded in advance. The configuration correction data refers to the data formed and recorded in the memory of the BMS according to the operating conditions of the battery before the system time for obtaining the measured battery data, which can be understood as the data to be called to realize the estimation and correction of the measured SOC. Generally speaking, the configuration correction data can be understood as the fact that when the preset current and preset voltage are satisfied, the corresponding measured SOC should be within the error range of its preset SOC, so as to correct the measured SOC to ensure that the correction is determined. The error between the target SOC and the actual SOC of the battery is small, which improves the accuracy of the target SOC. For example, when the preset current is 1.2C, the configuration correction data for the preset current of 1.2C stored in the correction data table is as follows:

[5%, 1.2C, V1, D1, C1]

[15%, 1.2C, V2, D2, C2]

[25%, 1.2C, V3, D3, C3]

[75%, 1.2C, V4, D4, C4]

[85%, 1.2C, V5, D5, C5]

[95%, 1.2C, V6, D6, C6]

Here, the SOC upper limit correction data is configuration correction data for realizing correction of the upper limit of the actual measured SOC. The SOC lower limit correction data is configuration correction data for realizing correction of the lower limit of the measured SOC.

As an example, after receiving the measured battery data, the BMS needs to query the pre-stored correction data table based on the measured current and measured voltage, and select the configuration correction data that matches the preset current and the measured current, and the preset voltage matches the measured voltage. It is determined as SOC upper limit correction data and SOC lower limit correction data. In this example, the BMS can select the configuration correction data whose preset voltage is closest to the measured voltage from all the configuration correction data whose preset current matches the measured current and whose preset voltage is greater than the measured voltage, and determine it as the SOC upper limit correction data; The preset current matches the measured current, and the preset voltage is smaller than the measured voltage, among all configuration correction data, the configuration correction data with the preset voltage closest to the measured voltage is selected as the SOC lower limit correction data.

S13: Determine the SOC upper limit threshold and the SOC lower limit threshold according to the measured accumulated historical power, the SOC upper limit correction data, and the SOC lower limit correction data.

The SOC upper limit threshold is an evaluation threshold used to compare and determine whether the upper limit of the measured SOC needs to be corrected. The SOC lower limit threshold is an evaluation threshold used to compare and determine whether or not to correct the lower limit of the actually measured SOC.

As an example, the BMS executes the threshold determination logic, processes the SOC upper limit correction data, and obtains the SOC upper limit threshold; and processes the SOC lower limit correction data, and obtains the SOC lower limit threshold. Understandably, since both the SOC upper limit correction data and the SOC lower limit correction data include not only the preset current and the preset voltage, but also the preset SOC, the preset accumulated current error, and the preset accumulated historical power; the BMS can execute the threshold determination logic in real time. , process the measured cumulative historical power and the preset SOC, the preset cumulative current error, and the preset cumulative historical power in the SOC upper limit correction data to determine the SOC upper limit threshold; execute the threshold determination logic in real time to determine the measured cumulative historical power and the SOC lower limit The preset SOC, the preset accumulated current error and the preset accumulated historical power in the corrected data are processed to determine the lower limit threshold of the SOC. In this example, the threshold determination logic refers to the logic that uses the measured accumulated historical power, the preset SOC, the preset accumulated current error, and the preset accumulated historical power as input parameters, and uses a pre-configured algorithm for processing.

S14: Correct the measured SOC by using the SOC upper limit threshold and the SOC lower limit threshold to obtain the target SOC.

Among them, the target SOC is the target SOC determined after correcting the measured SOC by using the SOC upper threshold and the SOC lower threshold.

As an example, after determining the SOC upper threshold and the SOC lower threshold, the BMS may use a preconfigured SOC correction logic to compare the measured SOC with the SOC upper threshold and the SOC lower threshold, so as to compare the measured SOC with the SOC lower threshold and the SOC upper threshold according to the measured SOC and the SOC lower threshold and the SOC upper threshold. The comparison results of , determine whether the measured SOC needs to be corrected, and in the case that it is determined that the measured SOC needs to be corrected, how to implement the correction of the measured SOC in detail. For example, when the measured SOC is not between the SOC lower threshold and the SOC upper threshold, the SOC compensation rule can be used to compensate the SOC lower than the SOC lower threshold, or to compensate the measured SOC greater than the SOC upper threshold, so as to make it the target determined after compensation The SOC is closer to the range of the SOC lower threshold and the SOC upper threshold, so as to ensure the smallest error between the target SOC and the actual SOC of the battery and the highest accuracy. The SOC compensation rule is a preset rule for compensating the measured SOC. Different compensation conditions and a compensation formula corresponding to each compensation condition can be configured in the SOC compensation rule, so as to determine the corresponding compensation condition according to the actual situation. The corresponding compensation formula is processed.

The battery SOC estimation method provided in this embodiment queries the correction data table according to the measured current and the measured voltage, and quickly determines the correction data of the upper limit of the SOC and the correction data of the lower limit of the SOC, so that the SOC estimation requires less resources and helps to provide real-time SOC estimation. ; Then determine the SOC upper threshold and SOC lower threshold based on the measured accumulated historical power, SOC upper limit correction data and SOC lower limit correction data, and use the SOC upper threshold and SOC lower threshold evaluation to correct the measured SOC, so that the output target SOC is more accurate , the error with the actual SOC of the battery is small, so that the SOC estimation can take into account the needs of high accuracy, low resource requirements and high real-time performance.

In one embodiment, step S12 is to query the correction data table according to the measured current and the measured voltage, and obtain the SOC upper limit correction data and the SOC lower limit correction data that match the measured current and the measured voltage, including:

S121: Query the correction data table based on the measured current, and obtain the SOC candidate correction data in the correction data table that matches the preset current and the measured current.

S122: Based on the measured voltage and the SOC candidate correction data, obtain the SOC upper limit correction data and the SOC lower limit correction data.

Wherein, the SOC candidate correction data includes: preset current, preset voltage, preset SOC, and preset accumulated historical power.

The SOC candidate correction data refers to configuration correction data matching the preset current with the measured current, that is, all configuration correction data corresponding to the preset current matching the measured current is determined as the SOC candidate correction data. In this example, the preset current matching the actual measured current may refer to a preset current equal to the actual measured current, or may be a preset current that is not equal to but closest to the actual measured current.

As an example, if the measured data of the battery is [SOC0, 1.2C, V0, D0, C0], when the actual measured current is 1.2C, all the configuration correction data corresponding to the preset current of 1.2C obtained from the correction data table are determined as SOC The candidate correction data, for example, the SOC candidate correction data are as follows:

[5%, 1.2C, V1, D1, C1]

[15%, 1.2C, V2, D2, C2]

[25%, 1.2C, V3, D3, C3]

[75%, 1.2C, V4, D4, C4]

[85%, 1.2C, V5, D5, C5]

[95%, 1.2C, V6, D6, C6]

In the above-mentioned SOC candidate correction data, when the preset current matches the measured current, the preset voltage is proportional to the preset SOC, that is, the larger the preset voltage, the larger the preset SOC.

Understandably, the preset voltage and the measured voltage in all SOC candidate correction data whose preset current matches the measured current can be processed in ascending or descending order to form a voltage sorting sequence. The SOC candidate correction data corresponding to the two preset voltages are respectively determined as the SOC upper limit correction data and the SOC lower limit correction data, so as to use the SOC upper limit correction data and the SOC lower limit correction data to correct the upper limit or lower limit of the measured SOC to ensure the final The accuracy of the determined target SOC reduces the error between the target SOC and the actual SOC of the battery.

In one embodiment, step S121, that is, query the correction data table based on the measured current, and obtain the SOC candidate correction data matching the preset current and the measured current in the correction data table, including:

S1211: If the preset current in the correction data table is equal to the measured current, use the first correction data corresponding to the preset current as the SOC candidate correction data.

S1212: If the preset current in the correction data table is not equal to the measured current, obtain the second correction data and the third correction data in the correction data table, and obtain the SOC pending data based on the measured current, the second correction data and the third correction data Correction data is selected, wherein the preset current in the second correction data is smaller than the measured current, and the preset current in the third correction data is greater than the measured current.

As an example, the BMS acquires the measured battery data in real time. The measured battery data includes the measured current, measured voltage, measured SOC, measured accumulated current error, and measured accumulated historical power. [SOC _T , _IT , V _T , D _T , C _T ] represents the measured data of the battery. For example, during the charging process of the battery, when the measured current of 1.2C is used to charge to the measured voltage V0, the real-time voltage correction method can be used to estimate the SOC of the measured current of 1.2C and the measured voltage V0 to obtain the measured SOC0, and calculate with the configuration correction data. The measured cumulative current error D0 and the measured cumulative historical power C0 are used to obtain the measured battery data [SOC0, 1.2C, V0, D0, C0].

As an example, the measured current may be compared with the preset current in all configuration correction data in the correction data table. If the preset current is equal to the measured current, the configuration correction data in which the preset current is equal to the measured current is determined as the first correction data, and the first correction data is the SOC candidate correction data. If the preset current is not equal to the measured current, sort the measured current and the preset currents in all configuration correction data to obtain a current sorting sequence, and determine the two configuration correction data adjacent to the measured current as the second correction data and Third correction data. For example, among the two preset currents adjacent to the measured current in the current sorting sequence, the configuration correction data in which the preset current is smaller than the actual measured current is determined as the second correction data; the two preset currents adjacent to the measured current in the current sorting sequence are determined as the second correction data; Among the currents, the configuration correction data in which the preset current is greater than the measured current is determined as the third correction data.

In one embodiment, step S1212, that is, obtaining the SOC candidate correction data based on the measured current, the second correction data and the third correction data, includes: using a data estimation formula to compare the measured current, the second correction data and the third correction data. Perform processing to obtain SOC candidate correction data.

The data estimation formula is ST=(Sa-Sb)*(IT-Ib)/(Ia-Ib)+Sb; if Sa is the preset voltage in the second modified data, Sb is the preset voltage in the third modified data , then ST is the preset voltage in the SOC candidate correction data; if Sa is the preset SOC in the second correction data, and Sb is the preset SOC in the third correction data, then ST is the SOC candidate correction data. Preset SOC; if Sa is the preset cumulative historical power in the second correction data, Sb is the preset cumulative historical power in the third correction data, then ST is the preset cumulative historical power in the SOC candidate correction data; I _T is the measured current; Ia is the preset current in the second correction data; Ib is the preset current in the third correction data.

In this embodiment, the BMS can directly determine the measured current as the measured current, and after determining the second correction data and the third correction data, can use the preset current and preset voltage in the second correction data and the third correction data , Preset accumulated current error and preset accumulated historical power and other specific values are processed with the measured current to determine the SOC candidate correction data.

As an example, the BMS uses a data estimation formula to process the measured current, the second correction data, and the third correction data to obtain the SOC candidate correction data; wherein, the data estimation formula is ST=(Sa-Sb)*(IT-Ib )/(Ia-Ib)+Sb; if Sa is the preset voltage in the second correction data, Sb is the preset voltage in the third correction data, then ST is the preset voltage in the SOC candidate correction data; if Sa is the preset SOC in the second correction data, Sb is the preset SOC in the third correction data, and ST is the preset SOC in the SOC candidate correction data; if Sa is the preset accumulation in the second correction data historical power, Sb is the preset cumulative historical power in the third correction data, ST is the preset cumulative historical power in the SOC candidate correction data; _IT is the measured current; Ia is the preset current in the second correction data ; Ib is the preset current in the third correction data.

For example, the second correction data [SOCa, Ia, Va, Da, Ca] is [75%, 1.3C, 3.458, 5AH, 30000AH], and the third correction data [SOCb, Ib, Vb, Db, Cb] is [75 %, 1.0C, 3.412, 6AH, 22000AH], when the measured current I _T =1.2C, the measured voltage estimation formula is V _T =(Va-Vb)*

(I0-Ib)/(Ia-Ib)+Vb=(3.458-3.412)*(1.2-1.0)/(1.3-1.0)+3.412=3.443, that is, the measured voltage V _T is 3.443; the measured cumulative current error formula is D _T =(Da-Db)*(I0-Ib)/(Ia-Ib)+Db=(5-6)*(1.2-1.0)/(1.3-1.0)+6=5.33; the measured cumulative current error D _T was 5.33. The formula for the measured cumulative historical electricity is C _T =(Ca-Cb)*(I0-Ib)/(Ia-Ib)+Cb=(30000-22000)*(1.2-1.0)/(1.3-1.0)+22000=27333 , that is, the measured cumulative historical power _CT is 27333, then the final measured battery data is [75%, 1.2C, 3.443, 5.33AH, 27333AH].

Further, the actual measured data of the battery also includes the actual measured accumulated current error; correspondingly, the SOC candidate correction data also includes the preset accumulated current error, then the second corrected data and the third corrected data also include the preset accumulated current error, then the BMS adopts The data estimation formula processes the measured current, the second correction data and the third correction data to obtain the SOC candidate correction data; wherein, the data estimation formula is ST=(Sa-Sb)*(IT-Ib)/(Ia-Ib )+Sb; if Sa is the preset accumulated current error in the second correction data, Sb is the preset accumulated current error in the third correction data, then ST is the preset accumulated current error in the SOC candidate correction data; I _T is the measured current; Ia is the preset current in the second correction data; Ib is the preset current in the third correction data.

The battery SOC estimation method provided in this embodiment can quickly determine the SOC candidate correction data based on the measured current, the second correction data and the third correction data based on the measured current, the second correction data and the third correction data, so as to The estimated SOC is corrected by using the obtained SOC candidate correction data to ensure the accuracy of the final target SOC and reduce the error with the actual SOC.

In one embodiment, step S122, that is, based on the measured voltage and the SOC candidate correction data, obtain the SOC upper limit correction data and the SOC lower limit correction data, including:

S1221: If the preset voltage in the SOC candidate correction data is greater than the measured voltage, determine the difference between the preset voltage and the measured voltage in the SOC candidate correction data as the first difference, and determine the SOC with the smallest first difference The candidate correction data is determined as the SOC upper limit correction data.

S1222: If the preset voltage in the SOC candidate correction data is smaller than the measured voltage, determine the difference between the measured voltage and the preset voltage in the SOC candidate correction data as the second difference, and determine the SOC with the smallest second difference The candidate correction data is determined as the SOC lower limit correction data.

As an example, if the measured data of the battery is [SOC0, 1.2C, V0, D0, C0], when the actual measured current is 1.2C, all the configuration correction data corresponding to the preset current of 1.2C obtained from the correction data table are determined as SOC The candidate correction data, for example, the SOC candidate correction data are as follows:

[5%, 1.2C, V1, D1, C1]

[15%, 1.2C, V2, D2, C2]

[25%, 1.2C, V3, D3, C3]

[75%, 1.2C, V4, D4, C4]

[85%, 1.2C, V5, D5, C5]

[95%, 1.2C, V6, D6, C6]

In the above-mentioned SOC candidate correction data, when the preset current matches the measured current, the preset voltage is proportional to the preset SOC, that is, the larger the preset voltage, the larger the preset SOC.

As an example, the measured voltage V0 is compared with the preset voltages V1, V2, V3, V4, V5 and V6. If the preset voltages V5 and V6 are greater than the measured voltage V0, at this time, the difference between the preset voltage V5 and the measured voltage V0 can be calculated, determined as the first difference V5-V0, and the preset voltage V6 and the measured voltage can be calculated. The difference between V0 is determined as the first difference V6-V0; then the first difference V5-V0 is compared with V6-V0, since the first difference V5-V0 is smaller than the first difference V6-V0, Therefore, the SOC candidate correction data [85%, 1.2C, V5, D5, C5] corresponding to the first difference V5-V0 may be determined as the SOC upper limit correction data. If the preset voltages V1, V2, V3 and V4 are all smaller than the measured voltage V0, then calculate the second difference values V0-V1, V0-V2, V0 between the measured voltage V0 and the preset voltages V1, V2, V3 and V4 respectively -V3 and V0-V4, since V0-V4 is the smallest, therefore, the SOC candidate correction data [75%, 1.2C, V4, D4, C4] corresponding to the second difference V0-V4 can be determined as the SOC lower limit correction data .

Understandably, the preset voltage and the measured voltage in all SOC candidate correction data whose preset current matches the measured current can be processed in ascending or descending order to form a voltage sorting sequence. The SOC candidate correction data corresponding to the two preset voltages are respectively determined as the SOC upper limit correction data and the SOC lower limit correction data, so as to use the SOC upper limit correction data and the SOC lower limit correction data to correct the upper limit or lower limit of the measured SOC to ensure the final The accuracy of the determined target SOC reduces the error between the target SOC and the actual SOC of the battery.

In one embodiment, step S13, that is, determining the SOC upper limit threshold and the SOC lower limit threshold according to the measured accumulated historical power, SOC upper limit correction data and SOC lower limit correction data, including:

S131 : Obtain an upper limit error value according to the measured cumulative historical power and the preset cumulative current error and the preset cumulative historical power in the SOC upper limit correction data, and determine the sum of the preset SOC and the upper limit error value in the SOC upper limit correction data is the SOC upper threshold.

S132: Obtain a lower limit error value according to the measured cumulative historical power and the preset cumulative current error and the preset cumulative historical power in the SOC lower limit correction data, and determine the difference between the preset SOC and the lower limit error value in the SOC lower limit correction data is the SOC lower limit threshold.

As an example, the BMS first uses the upper limit error value calculation formula to process the preset cumulative current error and preset cumulative historical power in the measured cumulative historical power and SOC upper limit correction data to obtain the upper limit error value. The upper limit error value calculation formula is Wu =Du+k*(C _T -Cu), C _T is the measured cumulative historical power, Du and Cu are the preset cumulative current error and preset cumulative historical power in the SOC upper limit correction data, Wu is the upper limit error value, k is the cumulative historical power attenuation coefficient. The accumulated historical power attenuation coefficient k can be obtained based on the battery cycle attenuation experimental data. For example, in the SOC upper limit correction data [85%, 1.2C, V5, D5, C5], the value of Du is D5, and the value of Cu is C5. Next, the BMS determines the sum of the preset SOCu and the upper limit error value Wu in the SOC upper limit correction data as the SOC upper limit threshold to limit the error upper limit corresponding to the preset SOCu, that is, the acceptable error upper limit for the preset SOCu.

As an example, the BMS first uses the lower limit error value calculation formula to process the preset accumulated current error and preset accumulated historical power in the measured accumulated historical power and the SOC lower limit correction data, and obtains the lower limit error value. The calculation formula of the lower limit error value is Wp =Dp+k*(C _T -Cp), C _T is the measured cumulative historical power, Dp and Cp are the preset cumulative current error and preset cumulative historical power in the SOC lower limit correction data, Wp is the lower limit error value, k is the cumulative historical power attenuation coefficient. The accumulated historical power attenuation coefficient k can be obtained based on the battery cycle attenuation experimental data. For example, in the SOC lower limit correction data [75%, 1.2C, V4, D4, C4], the value of Dp is D4, and the value of Cp is C4. Next, the BMS determines the sum of the preset SOCp and the lower limit error value Wp in the SOC lower limit correction data as the SOC lower limit threshold to limit the error lower limit corresponding to the preset SOCp, that is, the acceptable error lower limit of the preset SOCp.

In one embodiment, step S14, that is, using the SOC upper limit threshold and the SOC lower limit threshold to correct the measured SOC to obtain the target SOC, including:

S141: If the measured SOC is greater than the SOC upper limit threshold, determine the preset SOC in the SOC upper limit correction data as the target SOC.

S142: If the measured SOC is less than the SOC lower limit threshold, determine the preset SOC in the SOC lower limit correction data as the target SOC.

S143: If the measured SOC is not less than the lower SOC threshold, and the measured SOC is not greater than the SOC upper threshold, then the measured SOC is determined as the target SOC.

As an example, if the measured SOC is greater than the SOC upper limit threshold, it means that the measured SOC is greater than the acceptable error upper limit of the preset SOCu in the SOC upper limit correction data. In this case, the measured SOC is directly corrected to the preset SOCu in the SOC upper limit correction data. , that is, the preset SOCu in the SOC upper limit correction data is directly determined as the target SOC, so as to avoid an excessive error between the target SOC and the actual SOC of the battery. For example, the preset SOCu in the SOC upper limit correction data [85%, 1.2C, V5, D5, C5] is 85%, and the upper limit error value is 2%, then the SOC upper limit threshold is 87%, if the measured SOC _T is 88% , the preset SOCu in the SOC upper limit correction data is determined as the target SOC, that is, the target SOC is 85%.

As an example, if the measured SOC is less than the SOC lower limit threshold, it means that the measured SOC is less than the acceptable lower error limit of the preset SOCp in the SOC lower limit correction data. At this time, the measured SOC is directly corrected to the preset SOCp in the SOC lower limit correction data. , that is, the preset SOCp in the SOC lower limit correction data is directly determined as the target SOC, so as to avoid an excessive error between the target SOC and the actual SOC of the battery. For example, the preset SOCp in the SOC lower limit correction data [75%, 1.2C, V4, D4, C4] is 75%, and the lower limit error value is 2%, then the SOC lower limit threshold is 73%, then the SOC _T is 71%, Then, the preset SOCp in the SOC lower limit correction data is determined as the target SOC, and the target SOC is 75%.

As an example, if the measured SOC is not less than the SOC lower limit threshold, and the measured SOC is not greater than the SOC upper threshold threshold, it means that the measured SOC is not less than the acceptable lower error limit of the preset SOCp in the SOC lower limit correction data, and the measured SOC is not greater than the SOC upper limit correction If the preset SOCu in the data has an acceptable upper limit of error, the measured SOC is directly determined as the target SOC, which can ensure the accuracy of the target SOC and make the error between it and the actual SOC of the battery smaller. For example, when the SOC lower threshold is 73% and the SOC upper threshold is 87%, if the measured SOC is 80%, since 73%<80%<87%, the measured SOC is directly determined as the target SOC, that is, the target SOC is 80% , no correction is required.

In the battery SOC estimation method provided in this embodiment, the correction data table is queried according to the measured current and voltage in the measured battery data, and the SOC upper limit correction data and the SOC lower limit correction data are quickly determined from the limited configuration correction data, so that the SOC is estimated. It requires low resources and helps to provide real-time SOC estimation; then determine the SOC upper threshold and SOC lower threshold based on the measured accumulated historical power, SOC upper limit correction data and SOC lower limit correction data, and use the SOC upper threshold and SOC lower threshold to evaluate the actual measurement. The SOC is corrected so that the output target SOC has a high accuracy and a small error with the actual SOC of the battery, so that the SOC estimation can take into account the needs of high accuracy, low resource requirements and high real-time performance.

In one embodiment, the battery measured data further includes the measured accumulated current error. As shown in FIG. 2 , after step S11 , that is, after acquiring the measured data of the battery, the battery SOC estimation method further includes:

S21: Compare the measured accumulated current error and the current error tolerance value.

S22: If the actual measured cumulative current error is greater than the current error tolerance value, query the correction data table according to the measured current and measured voltage, and obtain the SOC upper limit correction data and the SOC lower limit correction data that match the measured current and measured voltage.

S23: If the actual measured accumulated current error is not greater than the current error tolerance value, update the configuration correction data in the correction data table based on the actual battery measured data.

Further, the measured data of the battery also includes the measured accumulated current error. The measured cumulative current error refers to the accumulation of all error powers after receiving the actual measured data of the battery, which can be represented by D _T. Generally speaking, the measured cumulative current error is re-statistic after each full or empty, and is calculated after full or empty. The accumulation of all error powers. It can be understood that the measured accumulated current error includes the sum of all error electric quantities before the system time and the accumulation of the error electric quantity formed by the current battery measured data. The error power here can be understood as the error between the measured SOC and the actual SOC of the battery.

The current error tolerance value is a pre-configured threshold for evaluating whether the configuration correction data in the correction data table needs to be updated. For example, the current error tolerance value may be 2% of the battery power.

As an example, the BMS will compare the measured cumulative current error with the preset current error tolerance value; if the measured cumulative current error is greater than the current error tolerance value, steps S12-S14 are executed to correct the measured SOC and output Target SOC to ensure the accuracy of the target SOC; if the measured cumulative current error is not greater than the current error tolerance value, the configuration correction data in the correction data table is updated based on the battery measured data, so as to realize the correction data table according to the actual operating conditions of the battery. The configuration correction data in the correction data table is updated to ensure the accuracy and real-time performance of the configuration correction data in the correction data table.

In this embodiment, since the physical condition of the battery changes in real time during the actual operation of the battery, such as the aging of the battery, the decrease of the total capacity of the battery, or the abnormal increase of the internal resistance, etc., the correction data table stored in the memory of the BMS when it leaves the factory is stored in the correction data table. The accuracy of the SOC estimation of the battery with changes in the physical condition is reduced by the configuration correction data of the battery. When the measured cumulative current error in the battery measured data is not greater than the current error tolerance value, the configuration correction data in the correction data table is updated based on the battery measured data. This helps to improve the accuracy of SOC estimation and correction for the subsequently acquired battery measured data.

Since the current value can be evaluated as an index that reduces the maximum difference, the accumulated current error is an index used to evaluate the deviation of the historical current from the preset current. The accumulated historical power is equivalent to the time validity of the records, and its unreliability will increase as the battery power increases; therefore, the preset SOC can be determined based on the measured current, the measured cumulative current error, and the measured cumulative historical power in the measured battery data. Perform unreliability calculations for different preset currents in all configuration correction data that are the same as the measured SOC, obtain the measured unreliable value of the battery measured data, and determine whether it is necessary to use the battery measured data to correct the configuration in the data table according to the measured unreliable value. Correction data is updated.

In one embodiment, the measured data of the battery includes the measured SOC, the measured current, the measured voltage, the measured cumulative current error, and the measured cumulative historical power, which can be represented by [SOC _T , _IT , _VT , _DT , _CT ]; configuration The correction data includes preset current, preset voltage, preset SOC, preset accumulated current error and preset accumulated historical power, which can be represented by [SOCn, In, Vn, Dn, Cn]. Step S23 is to update the configuration correction data in the correction data table based on the actual measured data of the battery, including:

S231: Acquire all the SOC primary selection correction data in the correction data table that match the preset SOC and the measured SOC, and determine the SOC primary selection correction data adjacent to the preset current and the measured current as the first correction data to be updated and the second correction data to be updated Correction data, the first correction data to be updated and the second correction data to be updated are determined as the correction data to be updated for SOC, the preset current in the first correction data to be updated is smaller than the measured current, and the preset current in the second correction data to be updated The current is greater than the measured current.

S232 : Process the measured battery data and the SOC correction data to be updated, and obtain the measured unreliable value corresponding to the battery measured data and the unreliable value to be updated corresponding to the SOC correction data to be updated.

S233 : If the measured unreliable value is smaller than the unreliable value to be updated, update the SOC correction data to be updated by using the actual measured data of the battery.

As an example, step S231 specifically includes: (1) First, compare the preset SOCs in all configuration correction data in the correction data table, and determine the configuration correction data matching the preset SOC and the measured SOC as the SOC primary selection correction data. For example, the configuration correction data whose preset SOC is equal to the measured SOC is determined as the SOC primary selection correction data, or the configuration correction data whose preset SOC is the closest to the measured SOC is determined as the SOC primary selection correction data. (2) The SOC primary selection correction data adjacent to the preset current and the measured current is then determined as the SOC screening correction data. For example, the preset current and the measured current in all the SOC preliminary selection correction data are sorted to form a current sorting sequence, and the SOC preliminary selection correction data corresponding to the two preset currents adjacent to the measured current in the current sorting sequence, that is, in the current sorting sequence In the current sorting sequence, the SOC primary selection correction data corresponding to the two preset currents before and after the measured current are respectively determined as the first correction data to be updated and the second correction data to be updated, and the first correction data to be updated and the second correction data to be updated are respectively determined. The correction data is determined as the SOC screening correction data, so as to determine whether the to-be-updated SOC correction data needs to be updated according to the battery measured data and the SOC correction data to be updated, which helps to ensure the accuracy of the subsequent battery SOC estimation algorithm. Among them, the preset current in the first to-be-updated correction data is smaller than the actual measured current, that is, among all the preset currents smaller than the actual measured current, the SOC primary selection correction data corresponding to the preset current with the smallest difference between the measured currents is the first to-be-measured current. Update correction data. The preset current in the second to-be-updated correction data is greater than the measured current, that is, among all the preset currents greater than the measured current, the SOC primary selection correction data corresponding to the preset current with the smallest difference between the measured currents is the second to-be-updated correction data.

As an example, step S232 specifically includes: using the unreliable value formula to process the actual measured data of the battery to obtain the measured unreliable value corresponding to the actual measured data of the battery; and using the unreliable value formula to process the SOC to be updated and corrected data to obtain the SOC The unreliable value to be updated corresponding to the corrected data to be updated, the unreliable value formula is Q(CTBm)=ABS(Io-CTBm)*f+Do*g+( _CT -Co)*h, Q(CTBm) is preset The unreliable value corresponding to the current CTBm is the measured unreliable value or the unreliable value to be updated; ABS is the absolute value function; Io is the current used to calculate the unreliable value, which is the measured current I _T or the preset current In; f is the current coefficient; Do is the accumulated current error used to calculate the unreliable value, which can be the measured accumulated current error D _T or the preset accumulated current error Dn; g is the accumulated current error coefficient; The cumulative historical power used to calculate the unreliable value may be the measured cumulative historical power _CT or the preset cumulative historical power Cn; h is the cumulative historical power coefficient. Understandably, f, g and h can be determined by the user based on experience.

In one embodiment, step S232 is to process the measured battery data and the SOC correction data to be updated, and obtain the measured unreliable value corresponding to the battery measured data and the unreliable value to be updated corresponding to the SOC correction data to be updated, including:

S2321: Use the measured unreliable value formula Q _T (CTBm)=ABS(IT _-CTBm )*f+ _{D T} *g+( _CT -CT )*h to calculate the battery measured data, and obtain the corresponding battery measured data Measured unreliable value.

S2322: Calculate the SOC to-be-updated corrected data and the battery measured data using the unreliable value formula to be updated Qn(CTBm)=ABS(In-CTBm)*f+Dn*g+(C _T -Cn)*h, and obtain the SOC to-be-updated data. Update the unreliable value to be updated corresponding to the correction data.

Among them, Q _T (CTBm) is the measured unreliable value corresponding to the actual measured data of the battery; CTBm is the preset current; ABS is the absolute value function; I _T , D _T and C _T are the measured current and the measured cumulative value of the measured battery data, respectively. Current error and measured accumulated historical power; Qn(CTBm) is the unreliable value to be updated corresponding to the SOC to be updated and corrected data; In, Dn and Cn are the preset current corresponding to the SOC to be updated and corrected data, the preset cumulative current error and The preset cumulative historical power; f is the current coefficient; g is the cumulative current error coefficient; h is the cumulative historical power coefficient.

The following example illustrates the process of updating the configuration correction data:

(1) Set the preset SOC to 75%, preset currents CTB1=0.2, CTB2=0.7, CTB3=1.2, CTB4=1.7 and CTB5=2.2, f=1000, g=10, h=0.01, for example, not The exact factor is the actual use factor, and the factor can be adjusted according to the battery and project conditions. In the initial state, five configuration correction data are obtained as follows:

CTB1=0.2C:null;

CTB2=0.7C:null;

CTB3=1.2C:null;

CTB4=1.7C:null;

CTB5=2.2C:null;

(2) When the measured SOC reaches 75, and the measured cumulative current error is not greater than the current error tolerance value (such as 2%), obtain the measured data of the first battery [75%, 1.0C, 3.356, 3AH, 28000AH], because CTB2 <1.0C<CTB3, therefore, the configuration correction data corresponding to CTB2 and CTB3 is the SOC to-be-updated correction data, wherein the configuration-correction data corresponding to CTB2 is the first to-be-updated correction data, and the configuration-correction data corresponding to CTB3 is the second to-be-updated Correction data, since in the initial state (1), the two SOC correction data to be updated are empty, therefore, the battery measured data can be directly used to update the SOC correction data to be updated, and the five configuration correction data obtained are as follows:

CTB1=0.2C:null;

CTB2 = 0.7C: [75%, 1.0C, 3.412, 6AH, 22000AH];

CTB3 = 1.2C: [75%, 1.0C, 3.412, 6AH, 22000AH];

CTB4=1.7C:null;

CTB5=2.2C:null;

(3) When the measured SOC reaches 75%, and the measured cumulative current error is not greater than the current error tolerance value (such as 2%), obtain the measured data of the second battery [75%, 0.3C, 3.356, 3AH, 28000AH], because CTB1<0.3C<CTB2, therefore, the configuration correction data corresponding to CTB1 and CTB2 is the SOC to be updated and corrected data, wherein the configuration correction data corresponding to CTB1 is the first to be updated and corrected data, and the configuration correction data corresponding to CTB2 is the second to be updated. To update the corrected data, according to the unreliable value formula, obtain the unreliable value to be updated corresponding to the corrected SOC data to be updated and the measured unreliable value corresponding to the measured battery data as follows:

The unreliable values to be updated corresponding to the SOC to-be-updated correction data are as follows:

CTB1=0.2C:null;

Qn(CTB1) is empty;

CTB2 = 0.7C: [75%, 1.0C, 3.412, 6AH, 22000AH];

Qn(CTB2)=(1.0–0.7)*1000+6*10+(28000–22000)*0.01=420;

The measured unreliable values corresponding to the measured battery data are as follows:

CTB1 = 0.2C: [75%, 0.3C, 3.356, 3AH, 28000AH];

Q _T (CTB1)=(0.3–0.2)*1000+3*10+(28000–28000)*0.01=130;

CTB2 = 0.7C: [75%, 0.3C, 3.356, 3AH, 28000AH];

Q _T (CTB2)=(0.7–0.3)*1000+3*10+(28000–28000)*0.01=430;

Since Qn(CTB1) is empty, QT( _CTB1 )=130, it needs to be updated; since Qn(CTB2)=420<QT ₍ CTB2)=430, no row update is required, the updated 5 configuration correction data are as follows :

CTB1 = 0.2C: [75%, 0.3C, 3.356, 3AH, 28000AH];

CTB2 = 0.7C: [75%, 1.0C, 3.412, 6AH, 22000AH];

CTB3 = 1.2C: [75%, 1.0C, 3.412, 6AH, 22000AH];

CTB4=1.7C:null;

CTB5=2.2C:null;

(4) When the measured SOC reaches 75%, and the measured cumulative current error is not greater than the current error tolerance value (such as 2%), obtain the measured data of the third battery [75%, 1.3C, 3.458, 5AH, 30000AH], because CTB3<1.3C<CTB4, therefore, the configuration correction data corresponding to CTB3 and CTB4 is the SOC to-be-updated correction data, wherein the configuration correction data corresponding to CTB3 is the first to-be-updated correction data, and the configuration correction data corresponding to CTB4 is the second to-be-updated correction data To update the corrected data, according to the unreliable value formula, obtain the unreliable value to be updated corresponding to the corrected SOC data to be updated and the measured unreliable value corresponding to the measured battery data as follows:

The unreliable values to be updated corresponding to the SOC to-be-updated correction data are as follows:

CTB3 = 1.2C: [75%, 1.0C, 3.412, 6AH, 22000AH];

Qn(CTB3)=(1.2–1.0)*1000+6*10+(30000–22000)*0.01=340;

CTB4=1.7C: null

Qn(CTB4) is empty;

The measured unreliable values corresponding to the measured battery data are as follows:

CTB3 = 1.2C: [75%, 1.3C, 3.458, 5AH, 30000AH];

Q _T (CTB3)=(1.3–1.2)*1000+5*10+(30000–30000)*0.01=150;

CTB4 = 1.7C: [75%, 1.3C, 3.458, 5AH, 30000AH];

Q _T (CTB4)=(1.7–1.3)*1000+5*10+(30000–30000)*0.01=450;

Since Qn(CTB3)=340>QT( _CTB3 )=150, it needs to be updated; since Qn(CTB4) is empty and QT( _CTB4 )=450, it needs to be updated, so the updated 5 configuration correction data are as follows:

CTB1 = 0.2C: [75%, 0.3C, 3.356, 3AH, 28000AH];

CTB2 = 0.7C: [75%, 1.0C, 3.412, 6AH, 22000AH];

CTB3 = 1.2C: [75%, 1.3C, 3.458, 5AH, 30000AH];

CTB4 = 1.7C: [75%, 1.3C, 3.458, 5AH, 30000AH];

CTB5=2.2C:null;

(5) When the measured SOC reaches 75%, and the measured cumulative current error is not greater than the current error tolerance value (such as 2%), obtain the measured data of the fourth battery [75%, 1.9C, 3.485, 4AH, 35000AH], because CTB4<1.9C<CTB5, therefore, the configuration correction data corresponding to CTB4 and CTB5 is the SOC to be updated and corrected data, wherein the configuration correction data corresponding to CTB4 is the first to be updated and corrected data, and the configuration correction data corresponding to CTB5 is the second to be updated. To update the corrected data, according to the unreliable value formula, obtain the unreliable value to be updated corresponding to the corrected SOC data to be updated and the measured unreliable value corresponding to the measured battery data as follows:

The unreliable values to be updated corresponding to the SOC to-be-updated correction data are as follows:

CTB4 = 1.7C: [75%, 1.3C, 3.458, 5AH, 30000AH];

Qn(CTB4)=(1.7–1.3)*1000+5*10+(30000–22000)*0.01=530;

CTB5=2.2C:null;

Qn(CTB4) is empty;

The measured unreliable values corresponding to the measured battery data are as follows:

CTB4 = 1.7C: [75%, 1.9C, 3.485, 4AH, 35000AH];

Q _T (CTB4)=(1.9–1.7)*1000+4*10+(35000–35000)*0.01=240

CTB5=2.2C: [75%, 1.9C, 3.485, 4AH, 35000AH];

Q _T (CTB5)=(2.2–1.9)*1000+4*10+(35000–35000)*0.01=340

Since Qn(CTB4)=530>QT( _CTB4 )=240, it needs to be updated; since Qn(CTB5) is empty and QT( _CTB5 )=340, it needs to be updated, so the updated 5 configuration correction data are as follows:

CTB1 = 0.2C: [75%, 0.3C, 3.356, 3AH, 28000AH];

CTB2 = 0.7C: [75%, 1.0C, 3.412, 6AH, 22000AH];

CTB3 = 1.2C: [75%, 1.3C, 3.458, 5AH, 30000AH];

CTB4 = 1.7C: [75%, 1.9C, 3.485, 4AH, 35000AH];

CTB5=2.2C: [75%, 1.9C, 3.485, 4AH, 35000AH];

By analogy, when the measured SOC reaches the preset SOC, and the measured cumulative current error is not greater than the current error tolerance value, the BMS can use the measured current, the measured cumulative current error and the measured cumulative historical power in the measured battery data to obtain the measured battery data. The corresponding measured unreliable value; and calculate the corresponding unreliable value to be updated by using the SOC to be updated correction data with the same preset SOC and the measured SOC, that is, to use the preset cumulative current error and the preset cumulative current error in the SOC to be updated correction data Historical power, obtain the unreliable value to be updated corresponding to the SOC to be updated correction data, and use the battery measured data corresponding to the measured unreliable value smaller than the unreliable value to be updated to update the SOC to be updated correction data, so as to realize the correction data in the table. The configuration correction data of the battery is updated in real time to ensure the reliability of the subsequent SOC estimation, and to avoid that the pre-stored configuration correction data in the correction data table cannot accurately correct the measured SOC when the physical condition of the battery changes.

For example, in the process of executing steps S11-S14 for the first time, in the process of processing the measured data of the battery corresponding to the measured current of 1.2C, the pre-stored [75%, 1.0C, A, B, C ] and [75%, 1.3C, E, F, G], the two configuration correction data are determined as SOC upper limit correction data and SOC lower limit correction data, respectively, in order to determine the final target SOC. After updating [75%, 1.0C, A, B, C] to [75%, 0.9C, A', B', C'], and then performing steps S11-S14 again, it is necessary to use [75%, The two configuration correction data, 0.9C, A', B', C'] and [75%, 1.3C, E, F, G], are the SOC upper limit correction data and the SOC lower limit correction data, respectively, so as to determine the final target SOC.

In one embodiment, before step S11 is executed, a correction data table needs to be determined in advance, specifically, the preset SOC and preset current in the correction data table need to be determined experimentally, so that the subsequent real-time update can be performed according to the actual operating conditions of the battery. Obtain the measured voltage corresponding to the preset SOC and the preset current, the measured cumulative current error, and the measured cumulative historical power.

In one embodiment, a battery management system is provided, including a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, the battery SOC estimation method in the above embodiment is implemented For example, S11-S14 shown in FIG. 1, or S21-S23 shown in FIG. 2, are not repeated here to avoid repetition.

In one embodiment, a computer-readable storage medium is provided, and a computer program is stored on the computer-readable storage medium. When the computer program is executed by the processor, the battery SOC estimation method in the above-mentioned embodiment is implemented, for example, S11 shown in FIG. 1 . -S14, or shown in S21-S23 shown in FIG. 2, to avoid repetition, details are not repeated here.

Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be implemented by instructing relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium , when the computer program is executed, it may include the processes of the above-mentioned method embodiments. Wherein, any reference to memory, storage, database or other medium used in the various embodiments provided in this application may include non-volatile and/or volatile memory. Nonvolatile memory may include read only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous chain Road (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

Those skilled in the art can clearly understand that, for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned functions can be allocated to different functional units, Module completion means dividing the internal structure of the device into different functional units or modules to complete all or part of the functions described above.

It should be understood that the size of the sequence numbers of the steps in the above embodiments does not mean the sequence of execution, and the execution sequence of each process should be determined by its functions and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present invention.

Those skilled in the art can clearly understand that, for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned functions can be allocated to different functional units, Module completion means dividing the internal structure of the device into different functional units or modules to complete all or part of the functions described above.

The above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: The recorded technical solutions are modified, or some technical features thereof are equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the present invention. within the scope of protection.

Claims (12)

1. A battery SOC estimation method, characterized by comprising:

acquiring actually measured data of the battery, wherein the actually measured data of the battery comprises actually measured current, actually measured voltage, actually measured SOC and actually measured accumulated historical electric quantity;

inquiring a correction data table according to the actually measured current and the actually measured voltage, and acquiring SOC upper limit correction data and SOC lower limit correction data matched with the actually measured current and the actually measured voltage;

determining an SOC upper limit threshold and an SOC lower limit threshold according to the actually measured accumulated historical electric quantity, the SOC upper limit correction data and the SOC lower limit correction data;

and correcting the actual measurement SOC by adopting the SOC upper limit threshold and the SOC lower limit threshold to obtain a target SOC.

2. The battery SOC estimation method according to claim 1, wherein said retrieving correction data tables based on the measured current and the measured voltage to obtain SOC upper limit correction data and SOC lower limit correction data that match the measured current and the measured voltage comprises:

inquiring a correction data table based on the measured current, and acquiring SOC (system on chip) to-be-selected correction data of which the preset current is matched with the measured current in the correction data table;

acquiring SOC upper limit correction data and SOC lower limit correction data based on the measured voltage and the SOC to-be-selected correction data;

the SOC candidate correction data comprises: the method comprises the steps of presetting current, presetting voltage, presetting SOC and presetting accumulated historical electric quantity.

3. The battery SOC estimation method according to claim 2, wherein the querying a correction data table based on the measured current to obtain SOC candidate correction data in which a preset current in the correction data table matches the measured current includes:

if the preset current in the correction data table is equal to the actually measured current, taking first correction data corresponding to the preset current as SOC (system on chip) to-be-selected correction data;

if the preset current in the correction data table is not equal to the actual measurement current, second correction data and third correction data in the correction data table are obtained, SOC (system on chip) correction data to be selected are obtained based on the actual measurement current, the second correction data and the third correction data, wherein the preset current in the second correction data is smaller than the actual measurement current, and the preset current in the third correction data is larger than the actual measurement current.

4. The battery SOC estimation method according to claim 3, wherein said obtaining SOC candidate correction data based on the measured current, the second correction data, and the third correction data, comprises:

processing the actually measured current, the second correction data and the third correction data by adopting a data estimation formula to obtain SOC correction data to be selected;

the data estimation formula is ST ═ (Sa-Sb) × (IT-Ib)/(Ia-Ib) + Sb; if Sa is a preset voltage in the second correction data and Sb is a preset voltage in the third correction data, ST is a preset voltage in the SOC correction data to be selected; if Sa is a preset SOC in the second correction data and Sb is a preset SOC in the third correction data, ST is a preset SOC in the SOC to-be-selected correction data; if Sa is preset accumulated historical electric quantity in the second correction data and Sb is preset accumulated historical electric quantity in the third correction data, ST is preset accumulated historical electric quantity in the SOC to-be-selected correction data; i is_TIs the measured current; ia is a preset current in the second correction data; ib is the predetermined current in the third correction data.

5. The battery SOC estimation method according to claim 2, wherein the acquiring the SOC upper limit correction data and the SOC lower limit correction data based on the measured voltage and the SOC candidate correction data includes:

if the preset voltage in the SOC to-be-selected correction data is larger than the actually-measured voltage, determining the difference value between the preset voltage and the actually-measured voltage in the SOC to-be-selected correction data as a first difference value, and determining the SOC to-be-selected correction data with the minimum first difference value as SOC upper limit correction data;

and if the preset voltage in the SOC to-be-selected correction data is smaller than the actual measurement voltage, determining the difference value between the actual measurement voltage and the preset voltage in the SOC to-be-selected correction data as a second difference value, and determining the SOC to-be-selected correction data with the minimum second difference value as SOC lower limit correction data.

6. The battery SOC estimation method of claim 1, wherein the determining an SOC upper limit threshold value and an SOC lower limit threshold value based on the measured accumulated historical electric quantity, the SOC upper limit correction data, and the SOC lower limit correction data includes:

acquiring an upper limit error value according to the actually measured accumulated historical electric quantity and a preset accumulated current error and a preset accumulated historical electric quantity in the SOC upper limit correction data, and determining a sum value of a preset SOC in the SOC upper limit correction data and the upper limit error value as an SOC upper limit threshold;

and acquiring a lower limit error value according to the actually measured accumulated historical electric quantity and a preset accumulated current error and a preset accumulated historical electric quantity in the SOC lower limit correction data, and determining a difference value between a preset SOC in the SOC lower limit correction data and the lower limit error value as an SOC lower limit threshold.

7. The battery SOC estimation method according to claim 1, wherein the correcting the measured SOC using the SOC upper threshold and the SOC lower threshold to obtain a target SOC comprises:

if the actual measurement SOC is larger than the SOC upper limit threshold value, determining a preset SOC in the SOC upper limit correction data as the target SOC;

if the actual measurement SOC is smaller than the SOC lower limit threshold, determining a preset SOC in the SOC lower limit correction data as the target SOC;

and if the actual measurement SOC is not smaller than the SOC lower limit threshold value and the actual measurement SOC is not larger than the SOC upper limit threshold value, determining the actual measurement SOC as the target SOC.

8. The battery SOC estimation method of claim 1, wherein the battery measured data further includes a measured accumulated current error;

after the acquiring the measured battery data, the method for estimating the SOC of the battery further includes:

comparing the actually measured accumulated current error with a current error tolerance value;

if the actually measured accumulated current error is larger than the current error tolerance value, executing the query correction data table according to the actually measured current and the actually measured voltage to obtain SOC upper limit correction data and SOC lower limit correction data matched with the actually measured current and the actually measured voltage;

and if the actually measured accumulated current error is not larger than the current error tolerance value, updating the configuration correction data in the correction data table based on the actually measured battery data.

9. The battery SOC estimation method according to claim 8, wherein the updating of the configuration correction data in the correction data table based on the battery measured data includes:

acquiring SOC initial selection correction data of which all the preset SOCs are matched with the actually measured SOCs in the correction data table, determining the SOC initial selection correction data of which the preset current is adjacent to the actually measured current as first to-be-updated correction data and second to-be-updated correction data, and determining the first to-be-updated correction data and the second to-be-updated correction data as SOC to-be-updated correction data, wherein the preset current in the first to-be-updated correction data is smaller than the actually measured current, and the preset current in the second to-be-updated correction data is larger than the actually measured current;

processing the battery measured data and the SOC to-be-updated correction data to obtain a measured unreliable value corresponding to the battery measured data and an updated unreliable value corresponding to the SOC to-be-updated correction data;

and if the unreliable value to be updated is empty or the actually measured unreliable value is smaller than the unreliable value to be updated, updating the corrected data to be updated of the SOC by adopting the actually measured data of the battery.

10. The method for estimating SOC of a battery as claimed in claim 9, wherein the processing the measured battery data and the corrected SOC data to be updated to obtain the unreliable measured value corresponding to the measured battery data and the unreliable updated value corresponding to the corrected SOC data to be updated includes:

using formula Q of actually measured unreliable values_T(CTBm)＝ABS(I_T-CTBm)*f+D_T*g+(C_T-C_T) Calculating the actually measured data of the battery by h to obtain actually measured unreliable values corresponding to the actually measured data of the battery;

adopting the formula Qn (CTBm) ═ ABS (In-CTBm) × f + Dn × g + (C) to be updated_T-Cn) × h calculates the SOC correction data to be updated and the battery measured data, and obtains an unreliable value to be updated corresponding to the SOC correction data to be updated;

wherein Q is_T(CTBm) is an actually measured unreliable value corresponding to the actually measured data of the battery; CTBm is a preset current; ABS is an absolute value function; i is_T、D_TAnd C_TRespectively obtaining the measured current, the measured accumulated current error and the measured accumulated historical electric quantity in the measured data of the battery; qn (CTBm) is an unreliable value to be updated corresponding to the correction data to be updated of the SOC; in, Dn and Cn are respectively a preset current, a preset accumulated current error and a preset accumulated historical electric quantity corresponding to the corrected data to be updated of the SOC; f is the current coefficient; g is an accumulated current error coefficient; h is the accumulated historical electric quantity coefficient.

11. A battery management system comprising a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the battery SOC estimation method according to any one of claims 1 to 10 when executing the computer program.

12. A computer-readable storage medium storing a computer program, wherein the computer program, when executed by a processor, implements the battery SOC estimation method according to any one of claims 1 to 10.

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